Ophthalmic surgical instruments and methods of use thereof

ABSTRACT

An ophthalmic surgical instrument includes a housing and a snare operably coupled to the housing. The snare is configured to transition between an insertion configuration and a deployed configuration, in which the snare is sized to encircle lenticular tissue. The ophthalmic surgical instrument is designed to prevent elevation and/or tilting of the lenticular tissue as the snare transitions toward the insertion configuration to divide the lenticular tissue.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.15/970,145, filed on May 3, 2018, the entire contents of which areincorporated by reference herein.

BACKGROUND Technical Field

The present disclosure relates to ophthalmic surgical instruments, andmore particularly, to ophthalmic surgical instruments and methods thatfacilitate the fragmentation and removal of a lens from a lens capsule.

Background of Related Art

Cataract surgery and other surgical procedures that treat lenticulartissue, such as, for example, the intraocular lens, are performed bymaking a small incision in the edge of the cornea, which provides accessto the anterior chamber and to the anterior surface of the lens capsule.Afterward, a generally circular incision called a capsulorhexis is madethrough the anterior surface of the lens capsule to provide surgicalaccess to the lens. An ophthalmic surgical instrument may be insertedthrough the capsulorhexis and used to fragment the cataractous lens tofacilitate its removal from the lens capsule. However, duringsegmentation by the surgical instrument, the distal portion of the lensmay be caused to shift undesirably in an upward (i.e., anterior)direction. Such movement may cause trauma to delicate adjacent eyestructures such as the lens zonule, lens capsule or, cornealendothelium.

Accordingly, a continuing need exists in the surgical arts for improvedtools and methods for safely fragmenting and removing a cataractouslens.

SUMMARY

In accordance with an aspect of the present disclosure, an ophthalmicsurgical instrument is provided and includes a housing and a snareoperably coupled to the housing. The housing has a handle body and ahollow shaft extending distally of the handle body. The snare includes alooped segment configured to move between a contracted configuration anda dilated configuration. In the dilated configuration, the loopedsegment assumes a diameter and shape approximating a diameter and shapeof a cataractous lens. The looped segment is configured to sever thecataractous lens upon moving toward the contracted configuration. Amajority of the looped segment overlaps with a lateral side of thehollow shaft when the looped segment is in the dilated configuration.

In aspects, a majority of the looped segment may be disposed proximallyof a distal end of the hollow shaft.

In aspects, the hollow shaft may define a lateral opening in the lateralside thereof. The looped segment may protrude from the lateral opening.

In aspects, the looped segment may include a proximal section disposedproximally of the lateral opening, and a distal section disposeddistally of the lateral opening.

In aspects, both the proximal and distal sections of the looped segmentmay be disposed proximally of a distal end of the hollow shaft when thelooped segment is in the contracted configuration.

In aspects, a majority of the distal section of the looped segment maybe disposed proximally of a distal end of the hollow shaft when thelooped segment is in the contracted configuration.

In aspects, the majority of the looped segment may overlap with thelateral side of the hollow shaft throughout the transition of the loopedsegment between the contracted and dilated configurations.

In aspects, the looped segment may define a length that is parallel witha central longitudinal axis defined by the hollow shaft. A majority ofthe length of the looped segment may be in side-by-side relation withthe lateral side of the hollow shaft.

In aspects, the snare may be a wire having a first end portionconfigured to be coupled to a lever of the housing, and a second endportion fixed relative to the housing. The looped segment may be formedbetween the first and second end portions of the wire.

In another aspect of the present disclosure, an ophthalmic surgicalinstrument for severing a cataractous lens is provided and includes ahousing, a snare operably coupled to the housing, and a pair of opposingarms operably coupled to the housing. The snare includes a loopedsegment configured to move between a contracted configuration and adilated configuration, in which the looped segment assumes a diameterapproximating a diameter of a cataractous lens. The looped segment isconfigured to sever the cataractous lens upon moving toward thecontracted configuration. The pair of arms are disposed on oppositesides of the looped segment of the snare. The pair of arms areconfigured to move between a collapsed configuration and an expandedconfiguration, in which the pair of arms extend outwardly relative tothe looped segment of the snare.

In aspects, the looped segment of the snare may define a first plane,and the pair of arms together may define a second plane that isperpendicular to the first plane.

In aspects, the pair of arms may be disposed in the second plane in boththe collapsed and expanded configurations.

In aspects, the pair of arms may define an acute angle therebetween whenin the expanded configuration.

In aspects, the pair of arms may be configured to pivot outwardly awayfrom one another and a longitudinal axis defined by the snare whenmoving toward the expanded configuration.

In aspects, the pair of arms may be axially movable relative to thehousing between a proximal position, in which the pair of arms aredisposed within the housing, and a distal position, in which the pair ofarms are disposed outside of the housing.

In aspects, the pair of arms may be configured to automatically movetoward the expanded configuration upon advancing toward the distalposition.

In aspects, each of the pair of arms may have a posterior surface thatdefines an arcuate recess dimensioned to conform to an anterior surfaceof a human lens.

In aspects, the pair of arms may be resiliently biased toward theexpanded configuration.

In aspects, the housing may include a first lever operably coupled tothe snare, and a second lever operably coupled to the pair of arms.Movement of the first lever may move the looped segment between thecontracted and dilated configurations, whereas movement of the secondlever may move the pair of arms between the collapsed and expandedconfigurations.

In aspects, the snare may be a wire having a first end portion coupledto the first lever, and a second end portion fixed relative to thehousing.

Further details and aspects of exemplary embodiments of the presentdisclosure are described in more detail below with reference to theappended figures.

As used herein, the terms parallel and perpendicular are understood toinclude relative configurations that are substantially parallel andsubstantially perpendicular up to about + or −10 degrees from trueparallel and true perpendicular.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure are described herein withreference to the accompanying drawings, wherein:

FIG. 1A is a top view of an ophthalmic surgical instrument in accordancewith an embodiment of the present disclosure, illustrating a snarethereof in a contracted configuration;

FIG. 1B is a top view of the ophthalmic surgical instrument of FIG. 1A,illustrating the snare in a dilated configuration and a pair ofstabilization elements in an open configuration;

FIG. 2A is a side cross-sectional view of the ophthalmic surgicalinstrument of FIG. 1A, illustrating the snare in the contractedconfiguration and the stabilization elements in the closedconfiguration;

FIG. 2B is a side cross-sectional view of the ophthalmic surgicalinstrument of FIG. 1A, illustrating the snare in the dilatedconfiguration and the stabilization elements in the open configuration;

FIG. 3A is a top cross-sectional view of the ophthalmic surgicalinstrument of FIG. 1A, illustrating the snare in the contractedconfiguration and the stabilization elements in the closedconfiguration;

FIG. 3B is a top cross-sectional view of the ophthalmic surgicalinstrument of FIG. 1A, illustrating the snare in the dilatedconfiguration and the stabilization elements in the open configuration;

FIG. 4A is a side view of another embodiment of an ophthalmic surgicalinstrument, illustrating a snare thereof in a contracted configuration;

FIG. 4B is a side view of the ophthalmic surgical instrument of FIG. 4A,illustrating the snare in a dilated configuration;

FIG. 5A is a side view of yet another embodiment of an ophthalmicsurgical instrument, illustrating a snare thereof in a contractedconfiguration; and

FIG. 5B is a side view of the ophthalmic surgical instrument of FIG. 5A,illustrating the snare in a dilated configuration.

DETAILED DESCRIPTION

Embodiments of the presently disclosed ophthalmic surgical instrumentsare described in detail with reference to the drawings, in which likereference numerals designate identical or corresponding elements in eachof the several views. As used herein and as is traditional, the term“distal” will refer to that portion of the ophthalmic surgicalinstrument which is further from the user (i.e., closer to the eye)while the term “proximal” will refer to that portion of the ophthalmicsurgical instrument which is closer to the user (i.e., further from theeye).

The present disclosure provides embodiments of an ophthalmic surgicalinstrument used to fragment cataractous lenticular tissue prior to itsremoval from a lens capsule. The ophthalmic surgical instrument includesa handle portion, a snare for enclosing and severing the lenticulartissue, and a pair of stabilization elements that are selectivelyextendable outwardly relative to the snare during actuation of thesnare. The stabilization elements may be any suitable structure thatextends outwardly from the distal end or from opposite sides of thesnare to overlay opposing sides of the lenticular tissue during itsdivision by the snare. As the snare is contracted about the lenticulartissue, the stabilization elements resist anterior shifting (i.e.,upward shifting) of the lenticular tissue, which may otherwise occur dueto the proximally-oriented force exerted on the lenticular tissue duringcontraction of the snare. In some embodiments, the ophthalmic surgicalinstrument is constructed so that a distally-extending cannula thereofacts as the stabilization element. These and other features andadvantages of the various embodiments of the disclosed ophthalmicsurgical instruments will be described below.

With reference to FIGS. 1A-3C, an exemplary embodiment of an ophthalmicsurgical instrument is illustrated and is generally designated 100. Theophthalmic surgical instrument 100 generally includes a housing 110, asnare 112 for severing lenticular tissue, and a pair of stabilizationelements, such as, for example, elongated arms 120, 122 that selectivelyexpand from a closed or collapsed configuration (FIGS. 1A, 2A, 3A) to anopen or expanded configuration (FIGS. 1B, 2B, 3B).

The housing 110 of the ophthalmic surgical instrument 100 has a handlebody 114 and first and second levers 116 a, 116 b slidably coupled tothe handle body 114. The handle body 114 may be ergonomic and have anelongated configuration. In embodiments, the handle body 114 may assumeany suitable shape, such as, for example, rounded, planar, rectangular,or the like. The handle body 114 has a tapered distal end portion 118dimensioned to assist in positioning the ophthalmic surgical instrument100 adjacent eye structure. The levers 116 a, 116 b may be configured assliders, buttons, triggers, or the like. In embodiments, the housing 110may include a cannulated member, such as, for example, a hollow shaft(not shown), extending distally from the distal end portion 118 of thehandle body 114 to facilitate entry of the ophthalmic surgicalinstrument 100 through a standard corneal incision.

The snare 112 of the ophthalmic surgical instrument 100 is operablycoupled to the first lever 116 a of the housing 110 and includes a firstend portion 112 a and a second end portion 112 b (FIGS. 2A and 2B). Thefirst end portion 112 a of the snare 112 is movable relative to thehousing 110, while the second end portion 112 b of the snare 112 isfixed relative to the housing 110. In particular, the first end portion112 a of the snare 112 is coupled to the first lever 116 a of thehousing via a first actuator rod 124, such that movement of the firstlever 116 a moves the first end portion 112 a of the snare 112, and thesecond end portion 112 b of the snare 112 is fixed to an inner tubularstructure 126 (FIGS. 3A and 3B) formed in the distal end portion 118 ofthe handle body 114. It is contemplated that the second end portion 112b of the snare 112 may be fixed to the inner tubular structure 126 ofthe handle body 114 by crimping, welding, adhesives, mechanicalinterlocks, or any other suitable structure or method.

With reference to FIGS. 2A and 2B, the snare 112 has a looped segment128 disposed at least partially outside of the housing 110. The loopedsegment 128 of the snare 112 is transitionable, via an actuation of thefirst lever 116 a, between an insertion or contracted configuration, asshown in FIGS. 1A, 2A, and 3A, and a deployed or dilated configuration,as shown in FIGS. 1B, 2B, and 3B. For example, a proximal retraction ofthe first lever 116 a moves the first end portion 112 a of the snare 112proximally away from the second end portion 112 b of the snare 112,thereby reducing the diameter of the looped segment 128. In contrast, adistal advancement of the first lever 116 a moves the first end portion112 a of the snare 112 distally toward the second end portion 112 b ofthe snare 112, thereby increasing the diameter of the looped segment 128of the snare 112. The looped segment 128 has a predefined shapedimensioned to closely encircle a lens when the looped segment 128 is inthe dilated configuration.

In embodiments, at least the looped segment 128 of the snare 112 may bea metal or polymer wire, tether, strap, belt, or the like, with anysuitable cross-section configuration configured to sever lenticulartissue during contraction of the looped segment 128 about the lenticulartissue.

For an exemplary description of further features of the snare 112 andthe mechanism of its operation, reference may be made to U.S. Pat. No.9,775,743, filed on Sep. 17, 2014, the entire contents of which beingincorporated by reference herein.

With continued reference to FIGS. 1B and 2A-3B, the stabilizationelements or arms 120, 122 of the ophthalmic surgical instrument 100 aredisposed on opposite sides of a longitudinal axis “X” defined by thesnare 112. The arms 120, 122 are configured to move from the closedconfiguration (FIGS. 1A, 2A, 3A) to the open configuration (FIGS. 1B,2B, 3B) to maintain lenticular tissue in its current location, typicallybut not always within its lens capsule, as will be described. Inembodiments, the arms 120, 122 may be configured to move independentlyof one another. The arms 120, 122 are illustrated as being linear, butit is contemplated that the arms 120, 122 may assume any suitable shape,such as, for example, wing-shaped, disc-shaped, plate-like, orpolygonal.

The arms 120, 122 may be resiliently-biased toward the openconfiguration by a biasing member, such as, for example, a coil spring130, disposed therebetween. As such, upon moving the arms 120, 122distally out of the handle body 114 or the hollow shaft (not shown) ofthe housing 110, the arms 120, 122 automatically expand outwardlyrelative to one another. The arms 120, 122 each have a proximal endportion 120 a, 122 a pivotably coupled to a hub 132, and a distal endportion 120 b, 122 b. In other embodiments, instead of being pivotable,the arms 120, 122 may be configured to shift laterally outward from thecollapsed configuration to the expanded configuration.

The hub 132 couples the arms 120, 122 to the second lever 116 b of thehousing 110. In particular, the housing 110 has a second actuator rod134 interconnecting the hub 132 and the second lever 116 b. Upon slidingthe second lever 116 b relative to the handle body 114, the secondactuator rod 134 transfers the sliding motion to the hub 132 to axiallymove the arms 120, 122 along the longitudinal axis “X” of the snare 112relative to the handle body 114 between a proximal position and a distalposition. In the proximal position, the arms 120, 122 are concealedwithin the inner tubular structure 126 of the handle body 110 or thehollow shaft when the hollow shaft is used. With the arms 120, 122disposed within the housing 110, the inner tubular structure 126 of thehandle body 119 (or the hollow shaft when used) maintains the arms 120,122 in the collapsed configuration, in which the arms 120, 122 areparallel with one another and the longitudinal axis “X” of the snare112, therefore assuming a reduced profile. Upon moving the arms 120, 122toward the distal position, the arms 120, 122 move distally out of thehousing 110 (the handle body 114 and/or the hollow shaft when used)allowing the outwardly-oriented bias of the biasing member 130 totransition the arms 120, 122 toward the expanded configuration. Inembodiments, rather than automatically moving toward the expandedconfiguration upon exiting the housing 110, the arms 120, 122 may beexpanded manually via a drive mechanism (not shown).

As shown in FIGS. 1B and 3B, in the expanded configuration, the arms120, 122 flare outwardly from opposite sides of the snare 112 to definean angle α between the arms 120, 122. In embodiments, the angle α may bebetween about 0.1 degrees and about 180 degrees. In embodiments, theangle α may be between about 10 degrees and about 90 degrees.

The arms 120, 122 together define and reside in a horizontal plane, andthe expanded looped segment 128 of the snare 112 defines and resides ina vertical plane that is aligned with the longitudinal axis “X” of thesnare 112. The arms 120, 122 remain the horizontal plane throughouttheir movement between the collapsed and expanded configurations. Thearms 120, 122 are parallel with the longitudinal axis “X” of the snare112 while the horizontal plane of the arms 120, 122 is perpendicularrelative to the vertical plane of the looped segment 128 of the snare112.

In embodiments, the arms 120, 122 may be axially movable in a directionperpendicular to the horizontal plane of the looped segment 128 toadjust a vertical position of the arms 120, 122 relative to the housing110 as well as lenticular tissue. For example, the housing 110 mayfurther include a third lever (not shown) coupled to the hub 132 formoving the arms 120, 122 vertically relative to the housing 110.

As best shown in FIGS. 2A and 2B, each of the arms 120, 122 has aposterior tissue-contacting surface 136. The posterior tissue-contactingsurface 136 of the arms 120, 122 may define an arcuate recess 138therein dimensioned to conform to an anterior surface of a lens of aneye. As such, upon deploying the arms 120, 122 over a lens, theposterior tissue-contacting surface 136 of each of the arms 120, 122cups the anterior surface of the lens, thereby providing increasedsurface contact between the arms 120, 122 and the lens. It iscontemplated that the posterior tissue-contacting surface 136 may have acoating or liner of pliable material, such as an elastomer to helpprotect vulnerable structures in the eye.

In operation, a small incision in the edge of a cornea is made toprovide access to an anterior chamber and an anterior surface of acataractous lens of a patient's eye “E” (FIG. 3B). A capsulorhexis ismade through the anterior surface of a lens capsule of the patient's eye“E,” thereby providing surgical access to the cataractous lens “L.” Withthe arms 120, 122 of the ophthalmic surgical instrument 100 disposed inthe proximal position within the housing 110, and the snare 112 in theinsertion configuration, as shown in FIGS. 2A and 3A, the hollow shaftof the housing 110 is inserted through the corneal incision and thecapsulorhexis to position the looped segment 128 of the snare 112adjacent the anterior surface of the lens “L.” Once in position, thefirst lever 116 a is advanced to move the first end portion 112 a of thesnare 112 distally, thereby transitioning the looped segment 128 fromthe insertion configuration to the deployed configuration, as shown inFIG. 2B. With the looped segment 128 in the deployed configuration, thesnare 112 is rotated about its longitudinal axis “X” (e.g., via rotationof the entire ophthalmic surgical instrument 100 or via a rotationmechanism (not shown) coupled to the snare 112) to rotate the loopedsegment 128 circumferentially about the lens to encircle the lens andposition the looped segment 128 so that the vertical plane defined bythe looped segment 128 bisects the lens.

With the looped segment 128 of the snare 112 in the selected positionnoted above, the second lever 116 b of the housing 110 may be advancedto move the arms 120, 122 from the proximal position to the distalposition. As noted above, as the arms 120, 122 move to the distalposition, the arms 120, 122 automatically transition from the closedconfiguration to the open configuration, as shown in FIGS. 1B and 3B.More specifically, the arms 120, 122 move distally along the anteriorsurface of the lens “L” while also expanding relative to one another andthe longitudinal axis “X” of the snare 112 to position the posteriortissue-contacting surface 136 (FIG. 2B) of each of the arms 120, 122over lateral side portions of the anterior surface of the lens “L.”

With the arms 120, 122 overlaying and in contact with the anteriorsurface of the lens “L,” the first lever 116 a may then be retracted totransition the looped segment 128 from the dilated configuration to thecontracted configuration, dividing the lens “L” into two hemisphericalsections. During constriction of the looped segment 128 about the lens“L,” the looped segment 128 may exert a proximally-oriented and/oranteriorly oriented force on a distal pole “P” of the lens “L.” However,since the arms 120, 122 are in position over the lens “L,” the arms 120,122 resist and/or prevent the distal pole “P” of the lens “L” fromshifting proximally out of the lens capsule notwithstanding theproximally-oriented force exerted thereon by the snare 112.

After one or more fragmentations of the lens “L” by the ophthalmicsurgical instrument 100, the fragmented sections of the cataractous lens“L” may then be removed from the eye “E” using any suitable mechanism,such as, for example, an ultrasonic aspirator.

In some embodiments, the snare 112 and/or the arms 120, 122 may bemechanically powered through an electric motor, a pneumatic powersource, a hydraulic power source, magnets, or the like. It is alsocontemplated that the ophthalmic surgical instrument 100 may beincorporated into a robotic surgical system.

With reference to FIGS. 4A and 4B, another embodiment of an ophthalmicsurgical instrument 200 is illustrated, similar to the ophthalmicsurgical instrument 100 described above. Due to the similarities betweenthe ophthalmic surgical instrument 200 of the present embodiment and theophthalmic surgical instrument 100 described above, only those elementsof the ophthalmic surgical instrument 200 deemed necessary to elucidatethe differences from ophthalmic surgical instrument 100 described abovewill be described in detail.

The ophthalmic surgical instrument 200 generally includes a housing 210and a snare 212 for severing lenticular tissue. The housing 210 of theophthalmic surgical instrument 200 has a handle body 214 and acannulated body, such as, for example, a hollow shaft 226 extendingdistally from the handle body 214. The hollow shaft 226 is dimensionedfor passage through a corneal incision and has a proximal end 226 aintegrally formed with or attached to the handle body 214.

The snare 212 of the ophthalmic surgical instrument 200 includes a firstend portion 212 a and a second end portion 212 b. The first end portion212 a of the snare 212 is movable relative to and within the hollowshaft 226 of the housing 210 via an actuation mechanism (not shown),while the second end portion 212 b of the snare 212 is fixed relative tothe housing 210. It is contemplated that the first end portion 212 a ofthe snare 212 may be axially movable within the hollow shaft 226 via anysuitable actuation mechanism, such as, for example, manual actuation orany suitable motorized actuation mechanism. The second end portion 212 bof the snare 212 may be fixed to an inner surface of the hollow shaft226 by crimping, welding, adhesives, mechanical interlocks, or any othersuitable structure or method.

The snare 212 has a looped segment 228 disposed protruding out of adistal end 226 b of the hollow shaft 226. The looped segment 228 of thesnare 212 is transitionable, via axial movement of the first end portion212 a of the snare 212, between an insertion or contractedconfiguration, as shown in FIG. 4A, and a deployed or dilatedconfiguration, as shown in FIG. 4B. For example, a proximal retractionof a lever (not shown) of the housing 210 moves the first end portion212 a of the snare 212 proximally away from the second end portion 212 bof the snare 212, thereby reducing the diameter of the looped segment228. In contrast, a distal advancement of the lever moves the first endportion 212 a of the snare 212 distally toward the second end portion212 b of the snare 212, thereby increasing the diameter of the loopedsegment 228 of the snare 212. The looped segment 228 has a predefinedshape dimensioned to closely encircle a lens when the looped segment 228is in the dilated configuration.

The looped segment 228 of the snare 212 differs from the looped segment128 of the snare 112 of the ophthalmic surgical instrument 100 of FIGS.1A-3B in that a majority of the looped segment 228 overlaps with thehousing 210 (e.g., the hollow shaft 226) rather than a majority of thelooped segment 228 being disposed distally of the housing 210. Thelooped segment 228 has a proximal section 228 a having a predefinedcurvature, and a distal section 228 b having a predefined curvature. Thedistal section 228 b of the looped segment 228 is disposed distally ofthe distal end 226 of the hollow shaft 226, and the proximal section 228a of the looped segment 228 is disposed below the hollow shaft 226 andproximally of the distal end 226 b of the hollow shaft 226.

The looped segment 228 further includes a pre-bent section 228 cextending from the second end portion 212 b of the snare 212. Thepre-bent section 228 c is disposed distally and outside of the housing210 and has a smaller radius of curvature relative to the proximal anddistal sections 228 a, 228 b of the looped segment 228 to position theproximal section 228 a of the looped segment 228 proximally of andunderneath the distal end 226 of the hollow shaft 226 of the housing210. The proximal section 228 a, the distal section 228 b, and thepre-bent section 228 c of the looped segment 228 may be fabricated fromthe same material or different materials. For example, the pre-bentsection 228 c may be fabricated from a less flexible material than theproximal and distal sections 228 a, 228 b of the looped segment 228 toensure that a majority of the looped segment 228 overlaps with thehollow shaft 226 throughout the transition of the looped segment 228between the contracted and dilated configurations.

The looped segment 228 defines a length “L” parallel with a centrallongitudinal axis “A” defined by the hollow shaft 226. The proximalsection 228 a of the looped segment 228 has a length “L1,” which isapproximately ½ or more of the overall length “L” of the looped segment228, and the distal section 228 b of the looped segment 228 has a length“L2,” which is less than ½ of the overall length of the looped segment228. In embodiments, the length “L1” of the proximal section 228 a ofthe looped segment 228 is approximately ¾ of the overall length “L” ofthe looped segment 228, and the distal section 228 b of the loopedsegment 228 has a length “L2,” which is approximately ¼ of the overalllength “L” of the looped segment 228. In this way, during use of theophthalmic surgical instrument 200, a majority of the looped segment 228overlaps with the housing 210 (e.g., the hollow shaft 226), such thatthe housing 210 is configured to rest on lenticular tissue during itsfragmentation to prevent upward movement thereof during constriction ofthe looped segment 228.

The looped segment 228 is fabricated from shape memory materials, suchas, for example, a nickel-titanium alloy to allow the looped segment 228to move to its predefined, dilated configuration. Other shape memorymaterials, such as shape memory plastics are also contemplated. In otherembodiments, the looped segment 228 may be fabricated from any suitablebiocompatible material including, but not limited to, stainless steel,titanium, silicone, polyimide, polyether block amide, nylon,polycarbonate, or combinations thereof.

In operation, a small incision in the edge of a cornea is made toprovide access to an anterior chamber and an anterior surface of acataractous lens of a patient's eye. A capsulorhexis is made through theanterior surface of a lens capsule of the patient's eye providingsurgical access to the cataractous lens. With the snare 212 of theophthalmic surgical instrument 200 in the insertion configuration, asshown in FIG. 4A, the hollow shaft 226 of the housing 210 is insertedthrough the corneal incision and the capsulorhexis to position a distalend portion of the hollow shaft 226 in an overlapping arrangement withthe anterior surface of the lens, and position the looped segment 228 ofthe snare 212 adjacent the anterior surface of the lens.

Once the looped segment 228 is in the appropriate position, the firstend portion 212 a of the snare 212 is advanced distally, therebytransitioning the looped segment 228 from the insertion configuration tothe deployed configuration, as shown in FIG. 4B. With the looped segment228 in the deployed configuration, the snare 212 is rotated about itslongitudinal axis “A” (e.g., via rotation of the entire ophthalmicsurgical instrument 200 or via a rotation mechanism (not shown)) torotate the looped segment 228 circumferentially about the lens toencircle the lens and position the looped segment 228 relative to thelens so that the plane defined by the looped segment 228 bisects thelens. Upon rotating the snare 212 to the selected position, the distalend portion of the hollow shaft 226 overlaps with the anterior surfaceof the lens and a majority of the looped segment 228 of the snare 212.

With the looped segment 228 of the snare 212 disposed about the lens,and the distal end portion of the hollow shaft 226 overlaying and incontact with the anterior surface of the lens, the looped segment 228 istransitioned from the dilated configuration to the contractedconfiguration, dividing the lens into two hemispherical sections. Duringconstriction of the looped segment 228 about the lens, the loopedsegment 228 may exert a proximally-oriented and/or anteriorly-orientedforce on a distal pole of the lens. However, since the distal endportion of the hollow shaft 226 is in position over the lens, the hollowshaft 226 resists and/or prevents elevation and/or tilting of the distalpole of the lens notwithstanding the proximally-oriented force exertedthereon by the closing snare 212.

After one or more fragmentations of the lens by the ophthalmic surgicalinstrument 200, the fragmented sections of the cataractous lens may thenbe removed from the eye using any suitable mechanism, such as, forexample, an ultrasonic aspirator.

With reference to FIGS. 5A and 5B, another embodiment of an ophthalmicsurgical instrument 300 is illustrated, similar to the ophthalmicsurgical instrument 200 described above. Due to the similarities betweenthe ophthalmic surgical instrument 300 of the present embodiment and theophthalmic surgical instrument 200 described above, only those elementsof the ophthalmic surgical instrument 300 deemed necessary to elucidatethe differences from ophthalmic surgical instrument 200 described abovewill be described in detail.

The ophthalmic surgical instrument 300 generally includes a housing 310and a snare 312 operably coupled to the housing 310 for severinglenticular tissue. The housing 310 of the ophthalmic surgical instrument300 has a handle body 314 and a cannulated body, such as, for example, ahollow shaft 326 extending distally from the handle body 314. The hollowshaft 326 is dimensioned for passage through a corneal incision and hasa proximal end 326 a integrally formed with or attached to the handlebody 314, and a closed distal end 326 b. In embodiments, the distal end326 b of the hollow shaft 326 may be open. The hollow shaft 326 definesa central longitudinal axis “B” and defines a lateral opening 330 in alateral side surface 332 thereof. The lateral opening 330 is laterallyoffset from the central longitudinal axis “B” and defines an axis “C”therethrough that is perpendicular to the central longitudinal axis “A”of the hollow shaft 326. The lateral opening 330 may be any suitableshape, such as, for example, circular, elongated, square, or the like.

The snare 312 of the ophthalmic surgical instrument 300 includes a firstend portion 312 a and a second end portion 312 b. The first end portion312 a of the snare 312 is movable relative to and within the hollowshaft 326 of the housing 310 via an actuation mechanism (not shown),similar to the actuation mechanism described above, while the second endportion 312 b of the snare 312 is fixed relative to the housing 310. Thesecond end portion 312 b of the snare 312 may be fixed to an innersurface of the hollow shaft 226 by crimping, welding, adhesives,mechanical interlocks, or any other suitable structure or method. Inother embodiments, both the first and second end portions 312 a, 312 bmay be axially movable.

The snare 312 has a looped segment 328 protruding out of the lateralopening 330 in the lateral side 332 of the hollow shaft 226. The loopedsegment 328 of the snare 312 is transitionable, via axial movement ofthe first end portion 312 a of the snare 312, between an insertion orcontracted configuration, as shown in FIG. 5A, and a deployed or dilatedconfiguration, as shown in FIG. 5B. For example, a proximal retractionof a lever (not shown) of the housing 310 moves the first end portion312 a of the snare 312 proximally away from the second end portion 312 bof the snare 312, thereby reducing the diameter of the looped segment328. In contrast, a distal advancement of the lever moves the first endportion 312 a of the snare 312 distally toward the second end portion312 b of the snare 312, thereby increasing the diameter of the loopedsegment 328 of the snare 312. The looped segment 328 has a predefinedshape dimensioned to closely encircle a lens when the looped segment 328is in the dilated configuration. In embodiments, both the first andsecond end portions 312 a, 312 b of the snare 312 may be movable tocontract or dilate the looped segment 328.

The looped segment 228 defines a length “L” parallel with a centrallongitudinal axis “B” defined by the hollow shaft 226. A majority of thelength “L” of the looped segment 328 is in side-by-side, parallelrelation with the lateral side 332 of the hollow shaft 326. Further, amajority of the looped segment 328 (i.e., at least half) is disposedproximally of the distal end 326 b of the hollow shaft 326. In this way,during use of the ophthalmic surgical instrument 300, the hollow shaft326 hangs over a majority of the looped segment 328, such that thehollow shaft 326 sits on a lens during lens fragmentation to preventupward movement of the lens as the looped segment 328 is constrictedthereabout.

The looped segment 328 includes a proximal section 328 a disposedproximally of the lateral opening 330, and a distal section 328 bdisposed distally of the lateral opening 330. Both the proximal anddistal sections 328 a, 328 b of the looped segment 328 are disposedproximally of the distal end 326 b of the hollow shaft 326 when thelooped segment 328 is in the contracted configuration, as shown in FIG.5A. When the looped segment 328 is in the dilated configuration, theproximal section 328 a of the looped segment 328 is disposed proximallyof the distal end 326 b of the hollow shaft 326, whereas a majority,e.g., at least about half, of the distal segment 328 b is disposedproximally of the distal end 326 b of the hollow shaft 326. As such, amajority of the looped segment 328 is disposed alongside the lateralside 332 of the hollow shaft 326 throughout the transition of the loopedsegment 328 between the contracted and dilated configurations.

The looped segment 228 is fabricated from shape memory materials, suchas, for example, a nickel-titanium alloy to allow the looped segment 228to move to its predefined, dilated configuration. Other shape memorymaterials, such as shape memory plastics are also contemplated. In otherembodiments, the looped segment 228 may be fabricated from any suitablebiocompatible material including, but not limited to, stainless steel,titanium, silicone, polyimide, polyether block amide, nylon,polycarbonate, or combinations thereof.

In operation, a small incision in the edge of a cornea is made toprovide access to an anterior chamber and an anterior surface of acataractous lens of a patient's eye. A capsulorhexis is made through theanterior surface of a lens capsule of the patient's eye providingsurgical access to the cataractous lens. With the snare 312 of theophthalmic surgical instrument 300 in the contracted configuration, asshown in FIG. 5A, the hollow shaft 326 of the housing 310 is insertedthrough the corneal incision and the capsulorhexis to position a distalend portion of the hollow shaft 326 in an overlapping arrangement withthe anterior surface of the lens, and position the looped segment 328 ofthe snare 312 adjacent the anterior surface of the lens.

Once the looped segment 328 is in the appropriate position, the firstend portion 312 a of the snare 312 is advanced distally, therebytransitioning the looped segment 328 from the contracted configurationto the dilated configuration, as shown in FIG. 5B. With the loopedsegment 328 in the deployed configuration, the snare 312 is rotatedabout its longitudinal axis “B” (e.g., via rotation of the entireophthalmic surgical instrument 300 or via a rotation mechanism (notshown)) to rotate the looped segment 328 circumferentially about thelens to encircle the lens and position the looped segment 328 relativeto the lens so that the plane defined by the looped segment 328 bisectsthe lens. Upon rotating the snare 312 to the selected position, the axis“C” defined through the lateral opening 330 in the hollow shaft 326extends perpendicularly through a center of the eye, whereby the hollowshaft 326 overlaps with the anterior surface of the lens and a majorityof the looped segment 328 of the snare 312.

With the looped segment 328 of the snare 312 disposed about the lens,and the hollow shaft 326 overlaying and in contact with the anteriorsurface of the lens, the looped segment 328 is transitioned from thedilated configuration to the contracted configuration, dividing the lensinto two hemispherical sections. During contraction of the loopedsegment 328 about the lens, the looped segment 328 may exert aproximally-oriented force on a distal pole of the lens. However, sincethe hollow shaft 326 is in position over the lens, the hollow shaft 326resists and/or prevents elevation and/or tilting of the distal pole ofthe lens notwithstanding the proximally-oriented force exerted thereonby the closing snare 312.

After one or more fragmentations of the lens by the ophthalmic surgicalinstrument 300, the fragmented sections of the cataractous lens may thenbe removed from the eye using any suitable mechanism, such as, forexample, an ultrasonic aspirator.

It will be understood that various modifications may be made to theembodiments disclosed herein. Therefore, the above description shouldnot be construed as limiting, but merely as exemplifications of variousembodiments. Those skilled in the art will envision other modificationswithin the scope and spirit of the claims appended thereto.

1. An ophthalmic surgical instrument, comprising: a housing; a snareoperably coupled to the housing and configured to transition between aninsertion configuration and a deployed configuration, in which the snareis sized to encircle lenticular tissue; and a pair of arms operablycoupled to the housing and disposed on opposite sides of the snare,wherein the pair of arms are configured to move between a closedconfiguration and an open configuration, in which the pair of arms flareoutwardly relative to a longitudinal axis defined by the snare.
 2. Theophthalmic surgical instrument according to claim 1, wherein the pair ofarms are parallel with one another and the longitudinal axis of thesnare when in the closed configuration.
 3. The ophthalmic surgicalinstrument according to claim 1, wherein the pair of arms define anacute angle therebetween when in the open configuration.
 4. Theophthalmic surgical instrument according to claim 1, wherein the pair ofarms are configured to pivot outwardly away from one another and thelongitudinal axis of the snare when moving toward the openconfiguration.
 5. The ophthalmic surgical instrument according to claim1, wherein the pair of arms are axially movable relative to the housingbetween a proximal position and a distal position.
 6. The ophthalmicsurgical instrument according to claim 5, wherein the pair of arms areconcealed within the housing when in the proximal position, and exposedto ambient conditions when in the distal position.
 7. The ophthalmicsurgical instrument according to claim 5, wherein the pair of arms areconfigured to automatically move toward the open configuration uponadvancing toward the distal position.
 8. The ophthalmic surgicalinstrument according to claim 1, wherein the pair of arms areresiliently-biased toward the open configuration.
 9. The ophthalmicsurgical instrument according to claim 1, wherein each of the pair ofarms has a posterior surface defining an arcuate recess dimensioned toconform to an anterior surface of an eye.
 10. The ophthalmic surgicalinstrument according to claim 1, wherein the housing includes: a firstlever operably coupled to the snare, such that movement of the firstlever moves the snare between the insertion and deployed configurations;and a second lever operably coupled to the pair of arms, such thatmovement of the second lever moves the pair of arms between the closedand open configurations.
 11. The ophthalmic surgical instrumentaccording to claim 10, wherein the snare is a wire having a first endportion coupled to the first lever and a second end portion fixedrelative to the housing.
 12. The ophthalmic surgical instrumentaccording to claim 1, wherein the snare has a looped segment disposeddistally of the housing, the looped segment dimensioned for receipt of acataractous lens when the snare is in the deployed configuration, andconfigured to sever the cataractous lens as the snare moves toward theinsertion configuration.
 13. An ophthalmic surgical instrument forsevering a cataractous lens, comprising: a housing; a snare operablycoupled to the housing and including a looped segment configured to movebetween a contracted configuration and a dilated configuration, in whichthe looped segment assumes a diameter approximating a diameter of acataractous lens, wherein the looped segment is configured to sever thecataractous lens upon moving toward the contracted configuration; and apair of arms operably coupled to the housing and disposed on oppositesides of the looped segment of the snare, wherein the pair of arms areconfigured to move between a collapsed configuration and an expandedconfiguration, in which the pair of arms extend outwardly relative tothe looped segment of the snare.
 14. The ophthalmic surgical instrumentaccording to claim 13, wherein the looped segment of the snare defines afirst plane, and the pair of arms together define a second plane that isperpendicular to the first plane.
 15. The ophthalmic surgical instrumentaccording to claim 14, wherein the pair of arms are disposed in thesecond plane in both the collapsed and expanded configurations.
 16. Theophthalmic surgical instrument according to claim 13, wherein the pairof arms define an acute angle therebetween when in the openconfiguration.
 17. The ophthalmic surgical instrument according to claim13, wherein the pair of arms are configured to pivot outwardly away fromone another and a longitudinal axis defined by the snare when movingtoward the expanded configuration.
 18. The ophthalmic surgicalinstrument according to claim 13, wherein the pair of arms are axiallymovable relative to the housing between a proximal position, in whichthe pair of arms are disposed within the housing, and a distal position,in which the pair of arms are disposed outside of the housing.
 19. Theophthalmic surgical instrument according to claim 18, wherein the pairof arms are configured to automatically move toward the expandedconfiguration upon advancing toward the distal position.
 20. Theophthalmic surgical instrument according to claim 13, wherein each ofthe pair of arms has a posterior surface defining an arcuate recessdimensioned to conform to an anterior surface of an eye.